Mushroom farming leftovers made hens healthier, eggs more stable, and production more efficient. Feeding laying hens spent oyster mushroom substrate (Pleurotus ostreatus) at 100 g/kg increased laying rate from 92.8% to 95.7% and egg mass from 59.3 to 61.8 g per hen per day, while improving fat digestibility and shell strength. Eggs showed up to 64% lower lipid oxidation and reduced protein damage during storage, alongside beneficial shifts in ovarian antioxidant and anti-inflammatory gene activity.